The present invention relates generally to clothes washing machines, preferably to clothes washing machines having a balance ring, and more particularly to a tub suspension for a horizontal axis clothes washing machine.
Conventional clothes washing machines include vertical axis clothes washing machines and horizontal axis clothes washing machines, where "vertical axis" and "horizontal axis" refer to the orientation of the axis of rotation of the clothes basket. The clothes basket is generally enclosed by, and rotatably attached to, the non-rotating tub, and the tub is generally enclosed by, and typically suspended from, the cabinet.
Conventional vertical axis clothes washing machines include those in which the tub is suspended from the cabinet by a rod and spring tub suspension subassembly which prevents the tub from striking the cabinet during washing. The subassembly includes a cylinder typically (pivotably) attached to the tub, a rod having a first end positioned within the cylinder and a second end (pivotably) attached to the cabinet, a piston positioned within the cylinder and attached to the first end of the rod, and a spring positioned within the cylinder between the first and second ends of the rod.
Conventional vertical axis clothes washing machines also include those having, a pair of balance rings with one balance ring being attached to the top and the other balance ring being attached to the bottom of the rotating clothes basket. The balance rings have circumferential cavities which are partially filled (typically between ten and ninety percent) with water, which are sealed, and which are independent of each other. The balance rings help balance an unbalanced load of clothes during the spin-dry cycle, as is known to those skilled in the art.
Known horizontal axis clothes washing machines lack balance rings and typically have the tub suspended by simple springs and damped from below by friction dampers or supported from below by shock absorber type struts. Such horizontal axis clothes washing machines tend to have their cabinet feet lift and tend to "walk" about during the spin-dry cycle, especially with a clothes-load unbalance, unless they are weighted or bolted down to the floor. Additionally, such horizontal axis clothes washing machines can transmit significant loads to the floor during the wash cycle. What is needed is a horizontal axis clothes washing machine which encompasses all of the following characteristics during both the wash and spin-dry cycles: small excursions; small bearing loads; small dynamic load transfer to the floor; and small weight.